| 摘要 |
PROBLEM TO BE SOLVED: To provide a power transmission device for rapidly and surely cutting of the transmission of an overload torque. SOLUTION: A gear part 7 serving as a torque limiter is coupled to a rotary member 5 which is rotated, integral with a pulley 3, so as to be axially movable in a rotationally limited condition, and is threadedly coupled to a hub 6 fixed to a shaft of a compressor, by a predetermined fastening torque. It is noted that the threaded coupling between the gear part 7 and the hub 6 is constituted in such a way that the fastening torque is decreased (loosened) by rotating the gear part 7 in the rotational direction of the pulley 3, relative to the hub 6. Thus, the compressor is locked so as to increase the load torque of the shaft 2 side. When the load torque becomes higher than the fastening torque of the gear part 7, the gear part 7 is rotated in the loosening direction, relative to the hub 6. As a result, the gear part 7 is axially moved while it is rotated integral with the rotary member 5, and accordingly, the threaded coupling with the hub 6 is released. Thus, the power transmission between the hub 6 and the rotary member 5 is cut off. |
